I have had my fair share of fun with car salespeople, over the past 20 years of driving etc.
Most recently, bought a new minivan for my wife (Hyundai Entourage if you are interested) and went to several places while doing final research etc. I have gotten to the point where I now take this approach, and stick to it. I tell the salesperson that I have been in sales (and it is true) for more than 12 years, and I hope to make it simple for them. No BS, tell them exactly where I am in the buying process, and let them have a crack at it.
Some try tricks, and I simply smile, and walk. No continued speaking to them, no 2nd chances, no answering phone calls thereafter. You have 1 chance to win my business, and I will sign today.
I visited a local Kia dealer (as the Hyundai and Kia are very similar - OK exactly the same, but with differing trim packages, based on nameplate - think Chrysler and Dodge in the old days, and you are there). Jackass followed me out to my Accord, after I walked during his "pitch".
Went to the local Hyundai dealer, and told them what it would take to do business today, had done the research, wanted the van, needed X off, willing to sign etc. More games, I walked again.
CALLED a dealer 40 miles away, and did a deal over the phone for $1 more than I wanted to pay. When local dealer called 2 days later, I simply explained what happened.
Tough business those guys are in, and the training is brutal (ever see King of Cars?) so I feel for them, but when a prospect walks in and lines up what it will take, and you know that you can, YOU DO. Rule #1 in sales - stay out of the way of a guy who is BUYING.
Rant off!